This invention relates to devices for driving a fluid-dispensing syringe and, more particularly, to motor driven devices used in conjunction with tubing sets having specially configured connectors.
An infusion device is generally used to control the automatic dispensing of fluids from a syringe, for example, to a capillary tube which in turn might introduce those fluids to a patient. In many cases, it is extremely important that the rate of fluid delivery be correctly selected and accurately controlled.
In the prior art, several types of infusion devices have been used. One type of device incorporates a housing for supporting a syringe and utilizes an electrical motor, and associated drive circuitry configured to drive the plunger of the syringe at a constant rate. Typically such a configuration incorporates a lead screw coupling between the electric motor and the plunger. Alternatively, direct gear couplers have been used. Stepper motors have also been used, but the power requirements for stepper motors have been greater than is desirable for a light, compact device.
In infusion device U.S. patent application Ser. No. 676,728, assigned to the same assignee as the present application, a spring-driven infusion device is shown in which two or more substantially constant spring forces can be selectively engaged to drive different capacity syringes.
It is also desirable to provide infusion devices that can accomodate different size syringes and that can provide different drive rates for the respective syringes in an automatic manner that is not dependent on operator selection. It is furthermore desirable to provide tubing sets for infusion devices that make the use of the devices more convenient. It is an object of the present invention to provide an improved infusion device with these characteristics.
Another object is to provide such an infusion device that operates automatically and reliably without excessive controls or control devices, that accommodates different size syringes, and that varies the drive rate for the syringe plunger according to the size of the syringe.
It is still another object to provide such an infusion device with improved means for detecting occlusion and emptying of the syringe.
Another object is to provide an infusion device that will cooperate with a specially configured tubing set connector for control of the operation of the infusion device.
Still another object is to provide a tubing set connector for rapid and reliable and sterile connection to an infusion device. Another object is to provide such a connector that will cooperate with an infusion device in determining the position of syringes in the infusion device and in controlling the speed of operation of a syringe plunger in the device accordingly.